Kathleen--

My understanding (from a talk on women and AIDS at the AAFP
meeting last year--no reference) was that there have been 6 reported US
cases of AIDS transmissions to breastfed babies whose mothers acquired the
infection after delivery. (Elizabeth Glaser and her daughter are probably
the most famous case; she acquired HIV from a transfusion after a
post-partum hemorrhage and transmitted it to her newborn daughter.)  The
breastmilk is presumed to be the source since there was no other source of
infection.  The speaker at this talk felt that a primary HIV infection
during lactation would be a serious potential source of transmission since
the viral load is very high.

On the other hand, babies who haven't acquired HIV infection before/during
birth from their previously infected moms would have a lower (but not 0)
risk of infection through breastfeeding until mom reaches the later stages
of the disease, when viral load again rises.

Since most babies aren't tested at the time of birth, the only general
statement about breastfeeding transmission is epidemiologic.  About 25% of
non-breastfed babies of HIV + moms are infected perinatally; about 30% of
breastfed babies of HIV+ moms are infected.  So there is a 20% increase in
risk attributable to breastfeeding.  (These are pre-AZT numbers; the 25%
risk is reduced to 8% by AZT treatment during pregnancy, I haven't seen
any new numbers including breastfeeding--presumably these moms are not
breastfeeding since they know they are HIV positive. Perhaps if we start
getting more information from Africa, where HIV is not an automatic
contraindication to breastfeeding, we'll have better numbers.)

It is now easier to measure the virus directly, so the fact that maternal
antibody is not cleared for a few months doesn't really matter now as it
did when we could only measure antibody.  It's possible to know if the
baby's infected at birth by testing cord blood

 --
Anne Montgomery, M.D.
[log in to unmask]
St.Peter HospitalFamily Practice Residency
Olympia, WA